Smallest, Cheapest 110VAC -> 20VDC, 10AMP Power Supply

Well, I have this idea for a patent ... but ... it requires a power supply ... and I can't find one that meets my needs.

I need to come up with the smallest, cheapest 110VAC -> 20VDC, 10AMP (or close to that) power converter (about 190 - 200 Watts), constant voltage.

Small means about 5" X 3" X 2".

Ideally, I would find some commercially available power supply for less than $100 a copy and adapt it ... but, no such luck. I can't find one that size at any price.

There seems to be a barrier at about 120 Watts. This is due (I think) to the U/L certification requirement for 30 cfm air flow (fans) to get any more power than about 120 watts. So, things above 120Watts get a lot bigger (about twice as big in terms of form factor).

But, maybe ... hopefully ... I'm wrong about that.

I have two design ideas and the primary factor that differentiates the two is cost. A small $100 or less unit makes my desired plan the best option. If price is above $100 then I must go to the second option (which allows a bigger power supply but requires lots more cables and other manufucturing ... it's not as good a design ... but it will work).

Patents are not concerned with price. Also, if this is only a suppoting component (aka. not a critical part of your novel idea) just write your requirements for this secondary device and don't worry about the precise implementation. Your patent only needs to describe your idea. It is not the same as an engineering document/plan. i.e. you don't take a patent to the factory. Took me a long time to figure that out too.